<!DOCTYPE html>
<script src="../include.js"></script>
<script>
  test(() => {
      const sheet = new CSSStyleSheet();
      const css = `
        @property --test {
          syntax: '<color>';
          inherits: false;
          initial-value: black;
        }
      `;
      sheet.replaceSync(css);
      document.adoptedStyleSheets = [sheet];
      println("PASS (Didn't crash)");
  });
</script>
